package com.example.java8;

import java.util.HashMap;
import java.util.Map;

public class LikeTest {

    public static void main(String[] args) {
        LikeTest likeTest = new LikeTest();
        Map<String,Double> map = new HashMap<>();
        for (int i = 0; i < 1000000; i++) {
            Double aDouble = likeTest.doLevenshtein("国家发展和改革委员会"+i, "发改委"+i);
            map.put("第" + i + "次", aDouble);
        }
        System.out.println("结束");

    }

    Double doLevenshtein(String str1, String str2) {
        if (null == str1 || null == str2) {
            return 0.0;
        }
        //计算两个字符串的长度。
        int len1 = str1.length();
        int len2 = str2.length();        //建立上面说的数组，比字符长度大一个空间
        int[][] dif = new int[len1 + 1][len2 + 1];        //赋初值，步骤B。
        for (int a = 0; a <= len1; a++) {
            dif[a][0] = a;
        }
        for (int a = 0; a <= len2; a++) {
            dif[0][a] = a;
        }
        //计算两个字符是否一样，计算左上的值
        int temp;
        for (int i = 1; i <= len1; i++) {
            for (int j = 1; j <= len2; j++) {
                if (str1.charAt(i - 1) == str2.charAt(j - 1)) {
                    temp = 0;
                } else {
                    temp = 1;
                }
                //取三个值中最小的
                dif[i][j] = min(dif[i - 1][j - 1] + temp, dif[i][j - 1] + 1,
                        dif[i - 1][j] + 1);
            }
        }
        //取数组右下角的值，同样不同位置代表不同字符串的比较
        //System.out.println("差异步骤：" + dif[len1][len2]);
        //计算相似度
        float similarity = 1 - (float) dif[len1][len2] / Math.max(str1.length(), str2.length());
        return Double.parseDouble(String.format("%.2f", similarity)) * 100.0;
    }

    private static int min(int... is) {
        int min = Integer.MAX_VALUE;
        for (int i : is) {
            if (min > i) {
                min = i;
            }
        }
        return min;
    }

}
